Resin-encapsulation semiconductor device and method for fabricating the same

Abstract

A resin-encapsulation semiconductor device of this invention includes a die pad for mounting a semiconductor element; a plurality of supporting leads; a semiconductor element; a plurality of leads disposed to have tips thereof opposing the die pad; metal wires; and an encapsulation resin for encapsulating the die pad excluding a bottom thereof, the leads excluding bottoms and outside edges thereof, connecting regions with the metal wires, the supporting leads and the semiconductor element. The outside edges of the leads are disposed on substantially the same plane as the side face of the encapsulation resin, and the tip of each lead has a thin portion where the thickness is reduced in an upper face thereof.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to a resin-encapsulation semiconductor device using a lead frame and a method for fabricating the same. More particularly, it relates to a resin-encapsulation semiconductor device in which a die pad for mounting a semiconductor element is exposed from an encapsulation resin and a method for fabricating the same, and furthermore, it relates to a thin and highly reliable resin-encapsulation semiconductor device in which a semiconductor element with a large package area ratio can be packaged and a method for fabricating the same. [0002] Recently, in order to cope with downsizing of electronic equipment, semiconductor components such as a resin-encapsulation semiconductor device are required to have a high packaging density. Also in accordance with the downsizing, the semiconductor components have become small and thin. Furthermore, the semiconductor components are required to have a multi-pin structure in spite of their c...

AI Technical Summary

Benefits of technology

[0025] In one aspect, the thin portion of each of the tips of the leads has a gently inclined face formed by reducing the thickness in the upper face thereof to substantially a half of a thickness of the leads.

[0038] According to the resin-encapsulation semiconductor device of this invention, since the tips of the leads opposing the die pad have the thin portions with the reduced thickness in the upper faces thereof, even when the upper face of the die pad is placed at the same level as the upper faces of the leads, the periphery of the semiconductor element mounted on the die pad can be close to the thin portions on the tip upper faces of the leads. As a result, while avoiding contact between the leads and the semiconductor element, a large semiconductor element can be mounted for realizing a CSP. Also, since the tips of the leads have the thin portions, there is no need to upset the semiconductor element by providing an elevated support on the die pad. Therefore, the chip area ratio can be increased so as to realize a resin-encapsulation semiconductor device with a small thickness. According to the resin-encapsulation semiconductor device of this invention, the chip area ratio in the package (encapsulation resin) can be increased to 70% or more, so as to realize a CSP.

[0039] In addition, in the case where the tip of each lead opposing the die pad has the thin portion with a gently inclined face formed by reducing the thickness to substantially a half of the thickness of the lead, the connecting regions with the metal wires can be less affected by stress applied to the lead externally or within the encapsulation resin. As a result, the reliability of the connection can be improved.

[0040] According to the method for fabricating a resin-encapsulation semiconductor device of this invention, since the tips of the inner leads opposing the die pad have the thin portions where the thickness is reduced in the upper faces thereof in the used lead frame, a semiconductor element having such a large size as to have its periphery close to the thin portions of the tips of the inner leads can be mounted. As a result, the chip area ratio in the resin-encapsulation semiconductor device can be increased for realizing a CSP, and thus, a resin-encapsulation semiconductor device with a small thickness can be fabricated.

[0041] Also, in the case where the used lead frame is composed of a plurality of lead units provided inside one metal plate outer frame and has the thin portions where the thickness is reduced between the respective lead units, the whole upper face over all the lead units of the lead frame can be encapsulated with an encapsulation resin. When the respective units are cut at the thin portions with the reduced thickness therebetween, the bases of the supporting leads and the inner leads can be cut, so as to obtain resin-encapsulation semiconductor devices each of which is in a rectangular parallelepiped shape and has the outside edges of the supporting leads and the inner leads disposed on the substantially same plane as the side face of the encapsulation resin. As a result, the fabrication efficiency for resin-encapsulation semiconductor devices can be improved.

Problems solved by technology

In particular, when a large semiconductor element is packaged, the thickness of the resin-encapsulation semiconductor device is greatly affected, and hence, it is impossible to attain, by using this structure, a small thickness with a large semiconductor element packaged.

Furthermore, the inner leads are encapsulated substantially on the single side, and hence, external impact or stress caused within the encapsulation resin may apply stress to the metal wires connected onto the inner leads, so that there may be fear of break and degradation of the reliability in the connection.

However, in consideration of the area of each lead included in a small package, it is very difficult to form a plurality of grooves on each inner lead and further secure a bonding area for the connection to a metal wire.

Therefore, in order to separate each resin-encapsulation semiconductor device from the lead frame after the encapsulation, it is necessary to cut the lead frame with a mold, which can be an obstacle to improve the fabrication efficiency.

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